The Universal Mobile Telecommunication System (UMTS) is one of the 3rd Generation mobile communication systems, and its network structure is composed of a Center Network (CN), a UMTS Terrestrial Radio Access Network (UTRAN) and a User Equipment (UE). An interface Uu between the UTRAN and UE is a radio interface, on which a protocol stack is divided into a physical layer (the first layer), a data link layer (the second layer) and a network layer (the third layer) according to its functions and tasks. A Radio Resource Control (RRC) sub-layer, located in the bottom layer and belonging to the access layer, is mainly used to provide functions, such as control and management of radio resources and so on.
Radio bearer control and connection mobility management are two of very important functions of the RRC sub-layer. Since the time at which the two processes occur is not close, the two functions may be implemented respectively by a Radio Bearer Control (RBC) module and a Connection Mobility Management (CMM) module. The RBC module is mainly used to process a reconfiguration message sent by the network side, including messages such as radio bearer establishment, radio bearer reconfiguration, radio bearer release, transport channel reconfiguration and physical channel reconfiguration and so on. The RBC module is responsible for configuring resources included in these messages to the bottom layer such as the Radio Link Control (RLC) sub-layer of the data link layer, the Media Access Control (MAC) sub-layer and the physical layer and so on, such that a terminal and the upper layer of the network side can perform normal interaction of data and signaling services. The CMM module is mainly used to process handover in the same Radio Access Technology (RAT) mode, handover of different RAT modes, cell update and UTRAN Registration Area (URA) update and so on, which are caused by mobile and service requirements, where one URA may contain a plurality of CELLs. Various processes of the RBC and CMM modules are all performed when the RRC sub-layer is in a connected state. The connected state of the RRC sub-layer, i.e., the state of the UE includes four states: a CELL-Forward Access Channel (FACH) state, a CELL-Dedicated Channel (DCH) state, a CELL-Paging Channel (PCH) state and a URA-PCH state.
In the process of mobility management, the CMM module at the UE side generates a CELL update message to send to the network side; the network side receives the message, and then the UTRAN may send a CELL update confirmation message on the dedicated or common control channel. The cell update confirmation message may include access layer resources required for the UE side. The process of mobility management may be processes of mobile information update, physical channel reconfiguration, transport channel reconfiguration, radio bearer release or radio bearer reconfiguration and so on depending on different resources included in the cell update confirmation message.
If a URA update process requires initiating, the CMM module at the UE side is required to assemble a URA update request message to send to the network side. The network side receives the message, and then the UTRAN may send a URA update confirmation message on the dedicated control channel or the common channel. The process may also include the mobile information update of the UE.
The methods for processing various resource reconfiguration processes in the process of mobility management are similar to those for processing resource reconfiguration processes in the RBC module. In addition, processing of these resource reconfiguration processes is relatively complicated. If the processing of the CMM and RBC modules is separated completely, all of their own resource reconfiguration functions will be implemented respectively, thus increasing complexity of the function implementation and decreasing a processing efficiency.